COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Cessna 177 Series Aeroplanes AD/CESSNA 177/28 Fuel Cap Alignment Placard 9/80 Applicability: Model 177 with S/Nos. 661, 17700001 to 17702752; Model 177RG with S/Nos. 177RG0001 to 177RG0177; Model F177RG with S/Nos. F177RG0001 to F177RG0177. Requirement: Action in accordance with Cessna SIL No. SE 80-59. Compliance: Within 100 hours time in service after 30 September 1980. Background: Correct alignment of flush fitting type fuel caps is essential for efficient operation of the fuel tank secondary vent system.